JP2008097006A - Photographic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photographic lens capable of performing a focus control by converting a residual defocusing amount left after an overlap correction is applied on a camera body side into an optimum residual driving amount on a photographic lens side. <P>SOLUTION: Regarding the photographic lens 3 that is mountable to the camera body 1 having a focus detecting means 19 for detecting the defocusing amount of each photographing optical system in the midst of the movement of photographic optical systems 5 and 7, the photographic lens 3 includes: an output means 31 for outputting first function information A obtained at detecting the focus among pieces of function information showing the relation between the defocusing amount and the moving amount of each of the photographic optical systems 5 and 7 to the camera body side, and also, outputting second function information B at correcting the defocusing amount DF1 to the residual defocusing amount DF2 on the camera body side based on the moving amount of each of the photographic optical systems 5 and 7 after the focus is detected to the camera body side; an in-lens conversion means 37 for converting the residual defocusing amount DF2 to the residual driving amount Z3 by using the second function information B; and a lens driving means 43 for driving the photographic optical systems 5 and 7 in accordance with the residual driving amount Z3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photographic lens that has a focus control drive mechanism on the photographic lens side that can be replaced with a camera body having a focus detection unit, and performs focus control of the photographic lens.

  2. Description of the Related Art Conventionally, as an autofocus system, a system that performs a defocus amount (shift amount between an imaging surface and an imaging surface) and a lens driving operation in parallel is known.

  In such an autofocus system, the detection value of the defocus amount must be corrected by the amount of lens movement after focus detection (hereinafter, such correction is referred to as “overlap correction”).

This kind of overlap correction is executed by the following procedures (1) to (3) on the camera body side.
(1) First, the defocus amount DF1 obtained by the focus detection unit is converted into the driving amount Z1 of the focusing lens in the photographing lens.
(2) The actually remaining drive amount (hereinafter referred to as “remaining drive amount”) Z3 is calculated by subtracting the lens movement amount Z2 after focus detection from the focus lens drive amount Z1.
(3) The remaining drive amount Z3 is divided by the conversion coefficient A (ratio between the drive amount and the defocus amount), and converted to the remaining defocus amount DF3.
The remaining defocus amount DF3 corrected in this way is transmitted to the photographing lens side.

  On the photographic lens side, the remaining defocus amount DF3 is multiplied by a conversion coefficient A ′ to calculate a remaining drive amount Z3 ′ that is a target drive value of the focusing lens. The drive mechanism in the photographic lens sequentially executes position control or speed control of the focusing lens according to the remaining drive amount Z3 ′.

The conversion coefficients A and A ′ described above are values that change every moment according to lens movement. Therefore, data indicating the correspondence between the lens position and the conversion coefficient is prepared in advance in the photographing lens. The latest conversion coefficient can be obtained by referring to this data based on the current lens position.
JP 63-304233 A

  Incidentally, in the above-described conventional example, both the photographing lens and the camera body acquire the conversion coefficients A and A ′ at independent timings. For this reason, the conversion coefficient A used on the camera body side does not necessarily match the conversion coefficient A ′ used on the photographing lens side.

  In general, in the case of a fully extended photographing lens, the change in the conversion coefficient depending on the lens position is small. Therefore, such a difference between the conversion coefficients A and A ′ is sufficiently negligible, and there is no problem in focusing accuracy.

  However, in an in-focus zoom lens or the like, the change of the conversion coefficient depending on the lens position is large. For this reason, when the lens position changes during the acquisition time of the conversion coefficients A and A ′, the conversion coefficients A and A ′ are greatly shifted.

  When the conversion coefficient A and the conversion coefficient A ′ are greatly deviated in this way, the normal remaining drive amount Z3 obtained on the camera body side and the remaining drive amount Z3 ′ actually used for focus control on the photographing lens side are calculated. There will be a discrepancy between them.

  Therefore, when using an in-focus zoom lens or the like, there are problems such as a decrease in focusing accuracy and a slow focusing speed.

  Therefore, in order to solve the above-described problem, a photographing lens capable of performing focus control by converting the remaining defocus amount subjected to overlap correction on the camera body side to an appropriate remaining driving amount on the photographing lens side. The purpose is to provide.

  The photographing lens according to claim 1 includes a photographing optical system and a focus detection means (19) for detecting a defocus amount of the photographing optical system during movement of at least a part (5, 7) of the photographing optical system. Among the function information representing the relationship between the defocus amount and the movement amount of at least a part (5, 7) of the photographing optical system in the photographing lens (3) that can be attached to the camera body (1) having a focus detection means The first function information (A) at the time of focus detection according to (19) is output to the camera body side, and the defocus amount (DF1) is based on the movement amount of at least a part of the photographing optical system after the focus detection time. Output means (31) for outputting the second function information (B) at the time of correction to the remaining defocus amount (DF2) on the camera body side and the second function information (B) using the second function information (B). In-lens conversion means (37) for converting the focus amount (DF2) into at least a remaining drive amount (Z3) of the photographing optical system, and the remaining drive amount (Z3) converted by the in-lens conversion means, And lens driving means (43) for driving at least a part of the photographing optical system.

  According to a second aspect of the present invention, in the photographing lens according to the first aspect, the in-lens conversion means converts the remaining defocus amount input from the camera body side using the second function information. Is corrected by at least a part of the movement amount of the photographing optical system after the correction time, and the lens driving unit drives at least a part of the photographing optical system according to the corrected remaining driving amount.

  According to a third aspect of the present invention, in the photographing lens according to the first or second aspect, the first function information or the second function information is selected in response to a request for function information from the camera body side. A data selection unit (27) and a data holding unit (35) for temporarily holding function information selected by the data selection unit are provided.

  According to a fourth aspect of the present invention, in the photographing lens according to the third aspect, the data selection unit (27) is arranged at at least a part of the position of the photographing optical system when the function information is requested from the camera body side. The function information is selected accordingly.

  The photographic lens according to claim 5 is the photographic lens according to any one of claims 1 to 4, further comprising storage means (29) for storing the first function information and the second function information. It is characterized by that.

  In the present invention, in the in-lens conversion means on the photographing lens side, the defocus amount is corrected at the camera body side to the remaining defocus amount based on the movement amount of at least a part of the photographing optical system after the focus detection time. 2 function information is output to the camera body side, and the remaining defocus amount is converted into at least part of the remaining drive amount of the photographing optical system using the second function information, so that the overlap correction is performed on the camera body side. It is possible to convert the remaining defocus amount subjected to the above to an appropriate remaining drive amount on the photographing lens side.

  By performing the focus control based on such an appropriate remaining drive amount, it is possible to increase the focusing accuracy and the focusing speed.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
(Configuration of the first embodiment)
FIG. 1 is a block diagram showing the system configuration of the first embodiment.

  In FIG. 1, a replaceable photographing lens 3 is attached to the camera body 1. In the photographing lens 3, a focusing lens 5, a zoom lens 7, and other lens groups are arranged. A main mirror 11, a sub mirror 13, a film surface 9 and the like are arranged in the camera body 1 along the optical axes of these lens groups.

  An AF sensor 17 is disposed in the reflection direction of the sub mirror 13. The output of the AF sensor 17 is connected to the body-side control unit 21 via a focus detection unit 19 that performs focus detection calculation. Information regarding the focus control output from the body side control unit 21 is transmitted to the AF control unit 37 via the data input unit 39 on the photographing lens 3 side.

  On the other hand, a focus position detecting unit 23 for detecting the absolute position of the focusing lens 5 and a zoom position detecting unit 25 for detecting the position of the zoom lens 7 are arranged on the photographing lens 3 side. The Outputs of these detection units 23 and 25 are connected to a data selection unit 27. The data selection unit 27 is connected to a memory 29 that stores lens information (for example, focal length information, shooting distance information, and conversion coefficient information).

  The lens information output from the data selection unit 27 is transferred to the body side control unit 21 via the data output unit 31. At this time, the lens information transferred to the body side control unit 21 is also sent to the data holding unit 35 in the photographing lens 3 and is recorded one by one as the lens information transferred immediately before.

  The output data of the data holding unit 35 is taken into the AF control unit 37. The AF control unit 37 drives the focusing lens 5 back and forth via the lens driving unit 43. The drive system for the focusing lens 5 is provided with a movement signal generator 45 composed of an encoder or the like. The lens movement signal output from the movement signal generator 45 is transmitted to the AF controller 37 and the body side controller 21.

(Operation of the first embodiment)
FIG. 2 is a flowchart for explaining the operation of the first embodiment. FIG. 3 is an explanatory diagram showing the relationship between the defocus amount and the drive amount.

  Hereinafter, the operation of the first embodiment will be described with reference to FIGS. 2 and 3.

  First, the body side control unit 21 causes the AF sensor 17 to start charge accumulation via the focus detection unit 19 (S1 in FIG. 2).

  The body-side control unit 21 requests a conversion coefficient from the AF control unit 37 on the photographing lens 3 side at an intermediate point in the charge accumulation period (hereinafter, this intermediate point is referred to as a focus detection point) (S2 in FIG. 2).

  On the photographing lens 3 side, the AF control unit 37 instructs the data selection unit 27 to generate a conversion coefficient. In response to such an instruction, first, the data selection unit 27 captures the lens positions of the focusing lens 5 and the zoom lens 7 from the focus position detection unit 23 (S3 in FIG. 2).

  Based on this lens position, the data selection unit 27 refers to the data table in the memory 29 and obtains the conversion coefficient A at the lens position at the time of focus detection. This conversion coefficient A is transferred to the camera body 1 side via the data output unit 31 (S4 in FIG. 2). In parallel with such a transfer operation, the data selection unit 27 temporarily holds the value of the conversion coefficient A in the data holding unit 35 (S5 in FIG. 2). Here, the conversion coefficient A is a value corresponding to the tan value of the angle θa shown in FIG.

  The body-side control unit 21 on the camera body 1 side takes in the conversion coefficient A and other lens data transferred in this way (S6 in FIG. 2).

  In parallel with the transfer operation of the conversion coefficient A, the body side control unit 21 starts counting the lens movement signal output from the movement signal generation unit 45 as needed (S7 in FIG. 2).

  The lens movement signal is a positive / negative two-phase pulse signal output in accordance with the back-and-forth movement of the focusing lens 5. Therefore, the movement distance of the focusing lens 5 after the counting start time can be detected in units of the number of pulses by counting the lens movement signals.

  Subsequently, when a predetermined charge accumulation period ends in the AF sensor 17, the focus detection unit 19 reads a data string indicating a pair of optical image patterns from the AF sensor 17 (S8 in FIG. 2).

  The focus detection unit 19 performs a correlation operation on these data strings to calculate a defocus amount value at the time of focus detection (S9 in FIG. 2). The defocus amount at this time corresponds to the defocus amount DF1 shown in FIG.

Here, the body-side control unit 21 calculates the drive amount Z1 necessary for driving the focusing lens 5 to the in-focus point by multiplying the defocus amount DF1 by the conversion coefficient A as shown in the following equation (1). (S10 in FIG. 2).
Z1 = DF1 × A (1)
The unit of the driving amount Z1 calculated here is the same unit as the number of pulses of the lens movement signal described above.

  At this time, the body-side control unit 21 finishes counting the lens movement signal, and obtains “lens movement amount Z2 after the focus detection time” as shown in FIG. 3 (S11 in FIG. 2).

Here, the body-side controller 21 subtracts the lens movement amount Z2 from the drive amount Z1 as shown in the following equation (2) to obtain the remaining drive amount Z3 at the time of correction (S12 in FIG. 2).
Z3 = Z1-Z2 (2)
Next, the body-side control unit 21 divides the remaining drive amount Z3 by the conversion coefficient A and converts it to the remaining defocus amount DF3 shown in FIG. 3 (S13 in FIG. 2).
DF3 = Z3 / A (3)
The body side control unit 21 transmits the remaining defocus amount DF3 to the photographing lens 3 side (S14 in FIG. 2).

  On the photographing lens 3 side, the AF control unit 37 acquires the remaining defocus amount DF3 (S15 in FIG. 2).

  Here, the AF control unit 37 reads the conversion coefficient A held in the data holding unit 35 (S16 in FIG. 2).

Subsequently, the AF control unit 37 obtains the remaining drive amount Z3 by multiplying the remaining defocus amount DF3 by the conversion coefficient A as shown in the following equation (4) (S17 in FIG. 2).
Z3 = DF3 × A (4)
The AF control unit 37 drives the focusing lens 5 via the lens driving unit 43 in a direction in which the remaining drive amount Z3 decreases (S18 in FIG. 2).

  The above operation is repeatedly executed, and when the count result of the lens movement signal output from the movement signal generation unit 45 becomes equal to the remaining drive amount Z3, the AF control unit 37 stops driving the lens.

(Effects of the first embodiment)
With the operation described above, in the first embodiment, since the data holding unit 35 that holds the conversion coefficient A is provided, the conversion coefficient A used in step S13 in FIG. 2 and the conversion coefficient A used in step S17 are provided. Always match.

  Therefore, even in the case where the value of the conversion coefficient varies greatly depending on the lens position, there is no discrepancy in the value of the remaining drive amount Z3 obtained between the camera body 1 side and the photographing lens 3 side. Therefore, on the photographing lens 3 side, it is possible to execute accurate automatic focus control based on the accurate remaining drive amount Z3 obtained by the camera body 1.

  Next, another embodiment will be described.

<Second Embodiment>
Since the configuration of the second embodiment is the same as that of the first embodiment (FIG. 1), description thereof is omitted here.

(Operation of Second Embodiment)
FIG. 4 is a flowchart for explaining the operation of the second embodiment. FIG. 5 is an explanatory diagram showing the relationship between the defocus amount and the drive amount.

  Hereinafter, the operation of the second embodiment will be described with reference to FIGS. 4 and 5.

  First, the body side control unit 21 causes the AF sensor 17 to start charge accumulation via the focus detection unit 19 (S1 in FIG. 4).

  The body side control unit 21 requests a conversion coefficient from the AF control unit 37 on the photographing lens 3 side at the time of focus detection (S2 in FIG. 4).

  On the photographing lens 3 side, in accordance with this request, first, the data selection unit 27 captures the lens positions of the focusing lens 5 and the zoom lens 7 from the focus position detection unit 23 (S3 in FIG. 4).

  Based on this lens position, the data selection unit 27 refers to the data table in the memory 29 and obtains the conversion coefficient A at the lens position at the time of focus detection. The conversion coefficient A is transferred to the camera body 1 side via the data output unit 31 (S4 in FIG. 4).

  In parallel with such a transfer operation, the data selection unit 27 temporarily holds the value of the conversion coefficient A in the data holding unit 35 (S5 in FIG. 4). Here, the conversion coefficient A is a value corresponding to the tan value of the angle θa shown in FIG.

  The body-side control unit 21 on the camera body 1 side takes in the conversion coefficient A and other lens data transferred in this way (S6 in FIG. 4).

  In parallel with the transfer operation of the conversion coefficient A, the body-side control unit 21 starts counting the lens movement signal output from the movement signal generation unit 45 at any time (S7 in FIG. 4).

  Subsequently, when a predetermined charge accumulation period ends in the AF sensor 17, the focus detection unit 19 reads a data string indicating a pair of light image patterns from the AF sensor 17 (S8 in FIG. 4).

  The focus detection unit 19 performs a correlation operation on these data strings to calculate a defocus amount value at the time of focus detection (S9 in FIG. 4). The defocus amount at this time corresponds to the defocus amount DF1 shown in FIG.

Here, the body-side control unit 21 calculates the drive amount Z1 necessary for driving the focusing lens 5 to the in-focus point by multiplying the defocus amount DF1 by the conversion coefficient A as shown in the following equation (5). (S10 in FIG. 4).
Z1 = DF1 × A (5)
At this time, the body-side control unit 21 finishes counting the lens movement signal, and obtains “lens movement amount Z2 after the focus detection time” as shown in FIG. 5 (S11 in FIG. 4).

Here, the body side controller 21 subtracts the lens movement amount Z2 from the driving amount Z1 as shown in the following equation (6) to obtain the remaining driving amount Z3 at the time of correction (S12 in FIG. 4).
Z3 = Z1-Z2 (6)
Next, the body side control unit 21 requests the lens side for a conversion coefficient at the time when these correction calculations are performed (hereinafter referred to as “correction time”) (S13 in FIG. 4).

  On the photographing lens 3 side, in accordance with this request, first, the data selection unit 27 captures the lens positions of the focusing lens 5 and the zoom lens 7 at the time of correction (S14 in FIG. 4).

  Based on this lens position, the data selection unit 27 refers to the data table in the memory 29 and obtains the conversion coefficient B at the lens position at the time of correction. The conversion coefficient B is transferred to the camera body 1 side via the data output unit 31 (S15 in FIG. 4).

  In parallel with such a transfer operation, the data selection unit 27 temporarily holds the value of the conversion coefficient B in the data holding unit 35 (S16 in FIG. 4). Note that the conversion coefficient B here is a value corresponding to the tan value of the angle θb shown in FIG.

  The body-side control unit 21 on the camera body 1 side takes in the conversion coefficient B transferred in this way (S17 in FIG. 4).

Next, the body-side control unit 21 divides the remaining drive amount Z3 by the conversion coefficient B and converts it to the remaining defocus amount DF2 shown in FIG. 5 (S18 in FIG. 4).
DF2 = Z3 / B (7)
The body side control unit 21 transfers the remaining defocus amount DF2 to the photographing lens 3 side (S19 in FIG. 4).

  Note that the value of the remaining defocus amount DF2 is converted using the conversion coefficient B at the time of correction, and thus indicates an accurate remaining defocus amount at the time of correction. Therefore, the body-side control unit 21 performs an operation such as in-focus determination based on the value of the remaining defocus amount DF2 (S20 in FIG. 4).

  On the other hand, on the photographic lens 3 side, the AF control unit 37 acquires the remaining defocus amount DF2 (S21 in FIG. 4).

  Here, the AF control unit 37 reads the conversion coefficient B held immediately before in the data holding unit 35 (S22 in FIG. 4).

Subsequently, the AF control unit 37 obtains the remaining drive amount Z3 by multiplying the remaining defocus amount DF2 by the conversion coefficient B as shown in the following equation (8) (S23 in FIG. 4).
Z3 = DF2 × B (8)
The AF control unit 37 drives the focusing lens 5 through the lens driving unit 43 in the direction in which the remaining drive amount Z3 decreases (S24 in FIG. 4).

  The above operation is repeatedly executed, and when the count result of the lens movement signal output from the movement signal generation unit 45 becomes equal to the remaining drive amount Z3, the AF control unit 37 stops driving the lens.

(Effects of the second embodiment, etc.)
Through the operation described above, the second embodiment can obtain the same effects as those of the first embodiment.

  Further, as an effect peculiar to the second embodiment, since the remaining drive amount Z3 is multiplied by the conversion coefficient B at the time of correction, the remaining defocus amount DF2 at the time of correction can be obtained without error. Therefore, it is possible to accurately execute in-focus determination at the time of correction based on the remaining defocus amount DF2.

  Next, another embodiment will be described.

<Third Embodiment>
Since the configuration of the third embodiment is the same as that of the first embodiment (FIG. 1), description thereof is omitted here.

(Operation of Third Embodiment)
FIG. 6 is a flowchart for explaining the operation of the third embodiment.

  Hereinafter, the operation of the third embodiment will be described with reference to FIGS. 5 and 6.

  First, the body side control unit 21 starts the charge accumulation of the AF sensor 17 via the focus detection unit 19 (S1 in FIG. 6).

  The body side control unit 21 requests a conversion coefficient from the AF control unit 37 on the photographing lens 3 side at the time of detecting the focus (S2 in FIG. 6).

  On the photographing lens 3 side, in accordance with this request, first, the data selection unit 27 captures the lens positions of the focusing lens 5 and the zoom lens 7 from the focus position detection unit 23 (S3 in FIG. 6).

  Based on this lens position, the data selection unit 27 refers to the data table in the memory 29 and obtains the conversion coefficient A at the lens position at the time of focus detection. The conversion coefficient A is transferred to the camera body 1 side via the data output unit 31 (S4 in FIG. 6). In parallel with such a transfer operation, the data selection unit 27 temporarily holds the value of the conversion coefficient A in the data holding unit 35 (S5 in FIG. 6). Here, the conversion coefficient A is a value corresponding to the tan value of the angle θa shown in FIG.

  The body side control unit 21 on the camera body 1 side takes in the conversion coefficient A and other lens data transferred in this way (S6 in FIG. 6).

  In parallel with the transfer operation of the conversion coefficient A, the body-side control unit 21 starts counting the lens movement signal output from the movement signal generation unit 45 at any time (S7 in FIG. 6).

  Subsequently, when a predetermined charge accumulation period ends in the AF sensor 17, the focus detection unit 19 reads a data string indicating a pair of optical image patterns from the AF sensor 17 (S8 in FIG. 6).

  The focus detection unit 19 performs a correlation operation on these data strings to calculate a defocus amount value at the time of focus detection (S9 in FIG. 6). The defocus amount at this time corresponds to the defocus amount DF1 shown in FIG.

Here, the body-side control unit 21 calculates the drive amount Z1 necessary for driving the focusing lens 5 to the in-focus point by multiplying the defocus amount DF1 by the conversion coefficient A as shown in the following equation (9). (S10 in FIG. 6).
Z1 = DF1 × A (9)
At this time, the body-side control unit 21 finishes counting the lens movement signal, and obtains “the lens movement amount Z2 after the focus detection time” as shown in FIG. 5 (S11 in FIG. 6).

Here, the body side controller 21 subtracts the lens movement amount Z2 from the drive amount Z1 as shown in the following equation (10) to obtain the remaining drive amount Z3 at the correction time (S12 in FIG. 6).
Z3 = Z1-Z2 (10)
Next, the body-side control unit 21 requests the lens side for the conversion coefficient at the time of correction (S13 in FIG. 6).

  On the photographing lens 3 side, in accordance with this request, first, the data selection unit 27 captures the lens positions of the focusing lens 5 and the zoom lens 7 at the time of correction (S14 in FIG. 6).

  Further, from this time point, the AF control unit 37 starts counting the lens movement signal output from the movement signal generation unit 45 (S15 in FIG. 6).

  The data selection unit 27 refers to the data table in the memory 29 based on the lens position, and obtains the conversion coefficient B at the lens position at the time of correction. The conversion coefficient B is transferred to the camera body 1 side via the data output unit 31 (S16 in FIG. 6).

  In parallel with such a transfer operation, the data selection unit 27 overwrites the value of the conversion coefficient B in the data holding unit 35 (S17 in FIG. 6). Note that the conversion coefficient B here is a value corresponding to the tan value of the angle θb shown in FIG.

  The body side control unit 21 on the camera body 1 side takes in the conversion coefficient B transferred in this way (S18 in FIG. 6).

Next, the body-side control unit 21 divides the remaining drive amount Z3 by the conversion coefficient B and converts it to the remaining defocus amount DF2 shown in FIG. 5 (S19 in FIG. 6).
DF2 = Z3 / B (11)
The body side control unit 21 transmits the remaining defocus amount DF2 to the photographing lens 3 side (S20 in FIG. 6).

  Note that the body-side control unit 21 performs operations such as in-focus determination based on the value of the remaining defocus amount DF2 (S21 in FIG. 6).

  On the photographing lens 3 side, the AF control unit 37 acquires the remaining defocus amount DF2 (S22 in FIG. 6).

  Here, the AF control unit 37 reads the conversion coefficient B held immediately before from the data holding unit 35 (S23 in FIG. 6).

Subsequently, the AF control unit 37 obtains the remaining drive amount Z3 by multiplying the remaining defocus amount DF2 by the conversion coefficient B as shown in the following equation (12) (S24 in FIG. 6).
Z3 = DF2 × B (12)
At this time, the AF control unit 37 once finishes counting the lens movement signal, and obtains the lens movement amount Z4 after the correction time (S25 in FIG. 6).

Here, the AF control unit 37 subtracts the lens movement amount Z4 from the remaining defocus amount Z3 as shown in the following equation (13) to obtain the remaining drive amount Z5 at the time of focus control (S26 in FIG. 6).
Z5 = Z3-Z4 (13)
The AF control unit 37 again counts the lens movement signal while driving the focusing lens 5 in the direction in which the remaining drive amount Z5 decreases through the lens driving unit 43 (S27 in FIG. 6).

  The AF control unit 37 stops driving the lens when the count result of the lens movement signal output from the movement signal generation unit 45 becomes equal to the remaining drive amount Z5 while the above operation is repeatedly executed.

(Effects of the third embodiment, etc.)
By the operation described above, the third embodiment can obtain the same effects as those of the second embodiment.

  Further, as an effect peculiar to the third embodiment, the remaining drive amount Z5 at the focus control time can be obtained by subtracting the lens movement amount Z4 after the correction time from the remaining drive amount Z3. Therefore, it is possible to execute more accurate automatic focus control based on the remaining drive amount Z5.

  In the above-described embodiment, the conversion coefficient is used as an example of the function information, but the present invention is not limited to this. Generally, “information indicating the relationship between the defocus amount and the drive amount” can be used as function information.

1 is a block diagram showing a system configuration of a first embodiment Flow chart for explaining the operation of the first embodiment Explanatory diagram showing the relationship between defocus amount and drive amount Flow chart for explaining the operation of the second embodiment Explanatory diagram showing the relationship between defocus amount and drive amount Flow chart for explaining the operation of the third embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera body 3 Shooting lens 5 Focusing lens 7 Zoom lens 11 Main mirror 13 Sub mirror 17 AF sensor 19 Focus detection part 21 Body side control part 23 Focus position detection part 25 Zoom position detection part 27 Data selection part 29 Memory 31 Data Output unit 35 Data holding unit 37 AF control unit 39 Data input unit 43 Lens drive unit 45 Movement signal generation unit

Claims (5)

In a photographic lens equipped with a photographic optical system and attachable to a camera body having a focus detection means for detecting a defocus amount of the photographic optical system during movement of at least a part of the photographic optical system,
Among the function information representing the relationship between the defocus amount and the movement amount of at least a part of the photographing optical system, the first function information at the time of focus detection by the focus detection unit is output to the camera body side, Second function information at the time of correcting the defocus amount to the remaining defocus amount on the camera body side based on the movement amount of at least a part of the photographing optical system after the focus detection time point to the camera body side. An output means for outputting;
In-lens conversion means for converting the remaining defocus amount into at least a partial remaining drive amount of the photographing optical system using the second function information;
An imaging lens comprising: lens driving means for driving at least a part of the imaging optical system in accordance with the remaining drive amount converted by the in-lens conversion means. The photographic lens according to claim 1,
The in-lens conversion unit is configured to convert the remaining drive amount obtained by converting the remaining defocus amount input from the camera body side using the second function information into at least one of the photographing optical systems after the correction time point. Corrected by the amount of movement of the
The lens driving unit drives at least a part of the photographing optical system according to the corrected remaining driving amount. The photographic lens according to claim 1 or 2,
A data selection unit that selects the first function information or the second function information in response to a request for the function information from the camera body;
An imaging lens, comprising: a data holding unit that temporarily holds the function information selected by the data selection unit. In the taking lens according to claim 3,
The photographic lens, wherein the data selection unit selects the function information according to a position of at least a part of the photographic optical system when the function information is requested from the camera body side. In the taking lens according to any one of claims 1 to 4,
A photographic lens comprising storage means for storing the first function information and the second function information.

Images